Category Archives: OpenGL

Small memory leak was driving me crazy; Debugging process was taking ages.. bored, frustrated and tired decided to play about with octrees depth and minimal/maximal number of elements in leaf.. Amazed by 300FPS discovered the stupid mistake of creating VBO each time the leaf is regenerated. Instant win; fix of memory leak and 10 times greater performance.

We can edit or remove current blocks – adding new ones will be introduced after optimisation stage. Current version supports 4 standard blocks (Blue, Green, Yellow, Brown) and 1 point light (Blue with circle in the middle).

In this iteration of “boxel engine” regenerateBuffers method updates nearest block that collides with ray fired from camera POV within worldGrid 3 dimensional table, after that, buffers that contain shadow and light powers are recalculated, at the end two openGL methods are called (for each buffer):

first, buffer is bind, and then values are updated, starting from index 0 and then updating whole buffer. Optimisation, that I will be introducing soon, is updating only changed values that will reduce data size. That has to be send to graphics card.

Shadow value for each cube is stored in separate grid, values are sent to shader and then output is altered. It all depends on value. The value is calculated based on number of obstacles on the way between light and current cube. Below you can find some metrics:

Metrics for shadow added.

Earlier I have introduced point light to engine, there is example of one point light – shown below.Point lights introduced.. performance drops.. but that's good.

Below 510 point lights on 64x64x64 cubes grid.

Point lights on 64 grid - 36 FPS.. pretty Ok.

And its metrics..

512 Point Lights took 2 Friends Episodes to load in

Metrics for grid of 32x32x32 cubes, below:

Wait.. What?!?.. straight Line?

Why the results for point lights are almost the same? All the calculations are precomputed on CPU so we are dealing with fixed buffer of light values – which is fair enough, however I need to optimise loading process so it will allow to add lights in real time.